SUO Fellow Mayo Clinic Rochester, MN, United States
Background: Venous tumor thrombus (VTT) is associated with worse oncologic outcomes in clear cell renal cell carcinoma (ccRCC). It is unknown if VTT is a predictor of pulmonary metastases.
Methods: We queried our institutional nephrectomy registry for ccRCC patients undergoing radical nephrectomy (1970-2019). Cox proportional hazards regression models, adjusting for factors associated with ccRCC progression, were used to determine if VTT was associated with pulmonary metastasis.
Results: Of the 3,410 patients, 1,025 (30%) had VTT, and patients with VTT were more likely to present with pulmonary metastasis at the time of nephrectomy (20% vs 7%, p< 0.001). Within the VTT subset, level of VTT was not significantly associated with pulmonary metastasis at nephrectomy (p=0.3). For all patients who had any site of metastatic disease at nephrectomy (n=643), pulmonary metastasis was more common in VTT versus without VTT (68% vs 51%, p< 0.001). Excluding patients with pulmonary metastasis at nephrectomy, VTT patients had a shorter pulmonary metastasis-free survival (Figure 1). On multivariable analysis, VTT remained associated with post-nephrectomy pulmonary metastasis (hazard ratio 1.31; 95% CI 1.12-1.53; p< 0.001) without a significant difference in hazard ratios between renal vein (1.27) and caval VTT (1.38). The presence of pulmonary embolism before or at nephrectomy was not associated with increased pulmonary metastasis after surgery.
Conclusions: VTT is associated with disproportionately increased pulmonary metastasis at presentation and post-nephrectomy in ccRCC patients. These results have implications for patient counselling, closer pulmonary surveillance, and understanding the biologic rationale of pulmonary tropism in these patients which can lead to development of more effective therapeutic targets.
